Process of sulphurizing oils



Patented July 1940 UNITED STATES PATENT OFFICE" PROCESS OF SULPHUBIZINGOILS Harry T. Bennett, Tulsa, Okla assig'nor to Mid- Continent PetroleumCorporation, Tulsa, Okla., a corporation of Delaware No Drawing.

1 Claim.

oils have been used to a considerable extent in the manufacture ofextreme pressure lubricants, and cutting oils. These sulphurized oilswhen blended with a mineral lubricating oil impart to the blended oilthe property of lubricating at extremely high pressures. It is to beunderstood that high temperatures result in the thickening of the oils,and that prolonged heating even at lower temperatures will also thickenthe oil. The present invention eliminates such thickening and produces asulphurized oil in the fluid state required for extreme pressurelubricants.

Heretofore, the cost of preparing sulphurized oils has beenobjectionable, as it has required relativelylong periods of time at hightreating temperatures to combine sulphur with oils. Moreover, duringthese relatively long processes at high temperatures, hydrogen sulphideis evolved and other sulphur products are formed during the reaction.

As an illustration of the conventional processes employed insulphurizing oils prior to my invention, I will refer to a treatmentwherein lard oil is sulphurized. The lard oil is heated to a temperatureof 325 F. with slow agitation in a suitable container. Sulphur is thenadded to the lard oil at the rate of 20 parts by weight of sulphur toparts of lard oil, and the resultant mixture stirred at 325 F. duringthe course of four to five hours, or until the sulphur is combined withthe oil. If it is desired to produce a product that will not corrodecopper, the resultant sulphurized mixture is then cooked at 325 F. foran additional hour or more until a bright highly polished copper stripexposed to the mixture shows no corrosion. When it is .unnecessary toproduce a product that will not corrode copper, the final cooking stepmay be omitted.

In commercial practice, there would be a very substantial reduction inthe cost of sulphurizing oils if the total reacting time of the oldprocesses could be reduced, or if lower treating temperatures could beemployed, or if both the time and temperatures were reduced.

I have found that certain compounds, which I term sulphur-combiningagents, when added in small quantities to the oil to be sulphurizedreduced the reaction time, or permitted the reaction to take place at alower temperature.

Application January 15, 1936, Serial No. 59,311

In carrying out my process,'the sulphur-combining agent is usually addedto the oil at the same time as the sulphur, but may be added just beforeor after the addition of the sulphur without any loss in efficiency. Theresultant mixture 5 is agitated at the desired reacting temperatureuntil thesulphur is combined with the oil. If it is desired to produce aproduct that will not corrode copper, the sulphurized mixture is thencooked until a polished copper strip immersed into the mixture shows nocorrosion. Any sulphur-combining agent which will pro-' mote the desiredreaction between the oil and sulphur may be employed in carrying out myprocess, 'and the following list is illustrative of various compoundswhich I have found satisfactory. Aromatic amino compounds:

Aniline Diphenyl guanidine 'I'riphenyl guanidine Methylene-p-toluidineDiorthotolyl guanidine Ethylidene aniline Heptaldehyde anilineFormanilide Butylaldehyde aniline Nitrosodimethylaniline Aromaticsulphur compounds:

Mercaptobenzthiazole Aromatic amino sulphur compounds:

Diphenyl thiourea Diethyl ammonium dlethyl dithiocarbamate' v the timeof reaction as compared to an example wherein no sulphur-combining agentwas employed.

Table I Qualntgty of su urcom ining gggg Sulphur-combining agent usedagent, time grams per hours 100 grams lard oil None None 4 10 2Hexamethylenetetramine 10 2% Tetramethyl thiuram disul hide 2 1% Diethylammonium diet yl dithiocarbamate 2 1% In each of the examples given inTable I, the same proportions'of lard oil and sulphur were employed, andin each instance the resultant products were stirred at 325 F. duringthe indicated reacting time.

As a further illustration of the efiect of sul- 1 phur-combining agentson the time of reaction, I have compared in the following Table II theuse of different quantities of diorthotolyl thiourea with an examplewhere no sulphur-combining agent was employed.

Table II Quantity of Tctal cr i r r i b i i i i n Reactin reactingSulphur-combining agent em g te g and used fig mpet' cooking glslams perature time,

grams lard oil hours F. None None 325 6% Diorthotolyl thiourea l l. 3253 D0 0. 25 325 4% The sulphur-combining agents will also permit areduction in reaction temperatures, as shown by the following Table III.

Table III Quantity of sulphur Total re- Sulphur-combining agent g g ag?acting used g n a time grams per reaction hour's 100 grams lard Oil F.None None 325 4 Do None 285 5% Diorthotolyl tbiourea 2 285 4 In each ofthe foregoing tables I have referred to lard oil as the materialtreated. However, it is not my intention to limit this invention to a.specific oil as the various animal, vegetable and mineral oils may besulphurized in accordance with my process.

As an illustration of the use of a sulphurcombining agent insulphurizing a mineral oil, I will refer to the treatment of a S. A. E.30 motor oil, with diorthotolyl thiourea. One hundred parts by weight ofthe oil were heated with 20 parts of sulphur and two parts ofdiorthotolyl thiourea and stirred at a temperature of 325 F. for eighthours. After this period of time the mixture showed no uncombinedsulphur.

As a comparison, the foregoing process employing the same materialsexcept for the sulphurcombining agent, was carried out for thirteenhours and even after this long heating period uncombined or free sulphurwas present in the mixture.

While I have given numerous specific examples of my process toillustrate the invention, it is understood that changes andmodifications may be made without departing from the spirit of theinvention, as set forth by the claim.

It is also understood that the invention is not limited to any'specificuse of the finished sulphurized oil. 1

Prior to this invention, compounds of the kind herein described havebeen employed in the rubber industry, as an aid in vulcanizing therubber. However, the present invention does not relate to vulcanization,and the product derivedirom the invention is a sulphurized oil, free ofconstituents resembling rubber.

I claim:

In the art of sulphurizing fatty and mineral oils the process ofavoiding thickening of the liquid oil which comprises heating a mixtureof the liquid oil and sulphur in the presence of an aromatic aminocompound selected from the group consisting of aniline, diphenylguanidine, triphenyl guanidine, methylene-p-toluidine, diorthotolylguanidine, ethylidene aniline, heptaldehyde aniline, formanilide,butylaldehyde aniline, and nitrosodimethylaniline, maintaining the 'oilat temperatures which retain it in a liquid condition durng the heatingoperation, limiting the temperature and time of said operation topositively prevent substantial thickening of the oil, and thencompleting the operation within said limits of temperature and time soas to convert the original liquid oil into a substantially non-thickenedsulphurized liquid.

HARRY T. BENNETT.

